Air cooled drive for draft fans



Sept.'l6, 1941. T MART AIR COOLED DRIVE FOR DRAFT FANS Filed Aug. 3, 1940 .mf w N .M N mw w .R NAR A mM T Nm wm um sw RN A ww n e. x. w m

Patented Sept. 16, 1941 circo srs AIR CGGLED DRIVE` FOR DRAFT FANS Leon T. Mart, Mission Township, Johnson County,

Kans., assigner to The Marley Company, Kansas City, Kans., a corporation of Missouri Application August 3, 1940, Serial No. 350,584

2 Claims.

This invention relates to cooling towers and particularly the apparatus therein for transmitting power to the draft producing fan thereof.

The primary aim of the instant invention is the provision of a specially formed self-cooling universal joint that is so combined with the fan drive of the cooling tower that currents of air constituting the draft created by the fan serve to maintain the relatively delicate parts of the u niversal joint at a temperature where disintegration is precluded. n

Another important object of this invention is the provision in a forced draft cooling tower, of drive means for the conventional fan, which drive means has as a part thereof, a universal joint protected against excessive temperatures due to flex.. ing, by a specially designed and disposed heat dissipating element, the nature of which is such as to employ the draft created by the fan when the parts are at work.

This invention contemplates specific objects in addition to those hereinabove set down, all of which will become apparent to one skilled in the art during a description of the embodiment illustrated in the accompanying drawing, wherein:

Figure 1 is a fragmentary sectional view through a cooling tower having an air cooled drive for the draft fan, made in accordance with the present invention.

Figs. 2 and 3 are enlarged fragmentary longitudinal sectional views through. portions of the air cooled drive, illustrating the manner of installing heat dissipating elements near the flexible coupling at each end of a relatively long drive shaft.

Fig. 4 is a fragmentary cross sectional view through one of the universal joints taken on line IV-IV of Fig. 2; and

Fig. 5 is a sectional view through a heat dissipating element embodying a modified form of the invention.

The problem of maintaining the temperatures of universal joints in cooling towers low enough to preclude destruction of the rubber coupling forming a part of said joints, has heretofore been troublesome, not only because the form of universal joint used was without correctly designed radiating elements, but because the fiexible member of the universal joint was improperly combined with metal parts to form a working connection between the drive and driven shafts. It has been found that power transmitting means such as that illustrated herewith, is rugged, efcient and long lasting, due to the particular manner in which the universal joint is constructed and the way of incorporating a heat dissipating element therein.

Forced draft cooling towers known in the art and produced by me, are equipped with a fan generally designated by the numeral 6, that has draft producing blades 8 and a speed reducer I0, all mounted upon a frame l2 which likewise carries sheathing lli which forms a throat I6 through .the passage whereof currents of air comprising the draft created by fan 6, are forced in the di rection of the arrows shown in Fig. l. n

A motor I8 carried by frame l2 is connected to speed reducer l0 through the medium of the unique drive means detailed in Figs. 2, 3 and 4. This drive means is joined at one end to motor drive shaft 2li, while the other end thereof is connected to driven shaft 22 forming a part of the speed reducer I. f

Motor I8 is accessibly mounted outside of sheathing i4 while of course, fan and speed reducer 6 and l0 respectively, are Within sheathing i4 in throat I6.

The distance between motor I8 and speed rcducer il! is sometimes relatively great and the angularity between drive shaft 20 and driven shaft 22 is such as to require universal joints -24 and 26 respectively, that establish a working connection between shafts 28 and shafts 20 and 22. When the invention is built into a cooling tower, these universal joints 24 and 26 must be in the paths of travel of the currents of air forming the draft produced by fan 6.

Universal joint 2li comprises a tting 36 secured to one end of shaft 28 and fastened to sleeve 32 by machine-screws 34. Sleeve 32 circumscribes a pair of rings 36 of substantially identical character but with different diameters so that when the rings 36Y are disposed concentrically, a space is left therebetween which is filled with a flexible rubber ller 38.

In practice the unit comprising rings 36 and ller 38 is made separately and then pressed to position within sleeve 32 and around bushing 4l) so that a tight connection is afforded. Filler 38 is secured directly to the proximal faces of rings 36 so that parts of the unit incorporating the same cannot relatively be displaced.

Bushing lill is keyed or otherwise fastened to drive shaft 2E! and in the form shown in Fig. 2, bushing 46 carries the specially created and disposed heat dissipating element 42. This element 42 is circular or ring-shaped and is flat with opposite sides converging so that the thickness of element 42 progressively decreases as the free edge is approached.

Element 42 is in metal-to-metal contact with bushing 40 and through the inner-ring 36, heat transfer may occur from filler 38 directly to the inclined faces 44 of element 42. These faces 44 intersect some of the currents of air forming the draft and rapid heat exchange advantageously affecting ller 38, is produced.

In commercial practice suitable exible material such as rubber in ller 38 will fail at 150 F. This temperature will be approached and passed in large installations unless element 42 is used. Air passing through throat I6 is usually at a temperature of 90 F. and is never above 100 to 110 F., therefore, if this air is employed as indicated above, to constantly bathe the faces of element 42, rubber constituting ller 38 will be protected against destructive heating. The universal joint illustrated in Fig. 3, is substantially like that .shown in Fig. 2, except element 45 is formed integrally with driven shaft 22. The inclined faces 48 of element 46 are disposed as described, with respect to element 42 and heat exchange is established through metal parts from flexible filler 58. This filler 56 is likewise carried by the two rings 52, the inner one of which is secured directly to a part of driven shaft 22. The outer ring 52 is encircled by sleeve 54 and a pressed t between all of these parts insures that no relative movement can occur except by the exing of the rubber constituting filler 58.

Sleeve 54 is secured to fitting 56 by machine screws or the like 58.

In some instances, elements 42 or 4% may be made to present more than two inclined faces whereupon the particular part may be created as illustrated in Fig. 5. This multiple element 50 has a series of annular fins 62 thereon, the

faces whereof are inclined enough to definitely 'intersect currents of air constituting the draft established by fan 6. Element B0 may be tightly pressed upon either bushing 32Y or 54 as the case may be, or may take the place of member V42 by merely projecting bushing 40 outwardly from the universal joint 24 a slightly greater dis tance along drive shaft 20.

Metal parts of universal joints 24 and 26 respectively should be carefully cast from material that is strong enough yet has the inherent capacity of conducting heat units to an ecient degree from the iiexible filler of the joints to the respective heat dissipating elements 42 and 46.

An air cooled drive for draft fans embodying the invention as above described and as hereinafter claimed, is extremely useful in heavy duty cooling towers, and while one form of the invention has been disclosed, it is desired to be limited in the enjoyment thereof only by the scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A drive coupling for cooling tower fans, comprising a shaft; a joint, provided with a flexible member completely isolating the shaft from the remaining parts of the drive coupling; and a heat dissipating element mounted on the drive coupling near the flexible member, said joint being a universal joint resulting in the constant flexing of said flexible member, said heat dissipating element having faces formed to intersect the paths of travel of currents of air created by the fan.

2. A drive coupling for cooling tower fans comprising a drive shaft; a driven shaft; a flexible coupling establishing connection between the said shafts; means for securing the flexible coupling to the drive shaft and the driven shaft to transmit power from the former to the latter; and a heat dissipating element in heat exchanging relation with said flexible coupling, said heat dissipating element being a ring encircling one of the shafts, and progressively decreasing in thickness. as the free edge is approached.

LEON T. MART.4 

